Internal-combustion engine.



ENGINE. 8,1913.

w. J. STILL INTERNAL COMBUSTION APPLICATION-FILED JAN. 1 1,145,392,

3 SHEETSSHEET 1.

Patented July 6, 1915.

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W. J. STILL. INTERNAL COMBUSTION ENGINE.

APPLICATION FILED JAN. 18, I913- Patented July 6, 1915.

3 SHEETSSHEET 2 lgsk W I. STILL.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED IAN.I ,19I3.

1,1 45,392. Patented July 6, 1915.

3 SHEETSSHEET 3- WILLIAM JOSEPH STILL, OF LONDON, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

and Connected with Internal-Combustion Engines, of which the following is a specification.

This invention relates to improvements in and connected with internal combustion engines and has particular reference to engines of that type wherein the waste heat of the engine is employed to generate or assist in the generation of steam for use expansively to increase the power of the engine.

It is of primary importance-particularly in this type of engine-to maintain the cylinders at a constant temperature throughout their Whole length, and in order to accomplish this and at the same time to advantageously utilize the large amount of heat usually lost to these cylinder walls, I provide as has previously been proposed an evaporating jacket surrounding the cylinders connected by influx and efllux pipes to a boiler drum so situated as to enable the water level within the drum to be maintained above the level of the crown of the jacket. The boiler drum will itself be heated by the exhaust from the combustion cylinders acting on suitable heating surfaces and separate firing means may if desirable be provided for starting up and overload purposes. Under these conditions the jacket will be maintained at the e aporating temperature of the boiler, say for example 380 F. instead of at about 180 F., which is a common outlet temperature for ordinary water jackets and this will render it essential that the cylinder walls be kept thin so as to reduce the difference between the tem perature of the inner and outer surfaces to a minimum.

My present invention consists primarily of a cylinder construction which renders this possible and this construction consists broadly in producing a thin cylinder strengthened by external pressure resisting means. This provision of a thin cylinder is of great importance in the case of large intei'nal engineswhether of this particular type or notwhich normally require to be of considerable thickness. It should be notedthat in speaking of a thin cylinder I mean a cylinder which without some extranc'ous strengthening means such as I propose to adopt would not be regarded in com- Specification of Letters Patent.

Application filed January ;8, 1913. Serial No. 742,878.

Patented J uly 6, 1915.

mon practice as sufliciently thick to stand the strains to which it is subjected.

To render the use of a thin cylinder wall possible without unduly weakening the cylinder as a whole, I propose to encircle the thin cylinder with a pressure resisting band separated from the cylinder by longitudinal ribs.- These ribs are preferably cast in one with the cylinder and extend over the high pressure zone, their outer faces or edges being turned to receive a wrought steel or. other suitable sleeve which is pressed over them. The ribs aforesaid are preferably thickened at their'roots to insure ample heat conducting areas. By this means the water flowing to the jacket will have access to parts comparatively close to the inner surfaces of the cylinder walls and yet ample strength will be provided to withstand the combustion pressures.

In the accompanying drawings I have illustrated my invention, Figurev 1 being a more or less diagrammatic View illustrating an engine cylinder in its preferable relation to the steam boiler or generator. Fig. 2 is a cross sectional plan view of the engine cylinder on line A-B of Fig. 1. Figs. 3 and 4 are sectional elevations on planes at right angles to each other of modified applications of my invention. Fig. 5 is a plan of the cylinder with the cover removed. Fig. 6 is a sectional elevation of an engine having opposed pistons and the combustion chamber between them with-my invention embodied therein and adapted thereto. Fig. 7 shows a modified method of performing my invention after the manner shown in Fig. 6.

Referring to these drawings and particularly to Figs. 1 and 2 the numeral 1 designates the cylinder provided with a piston 2 which is coupled up to the crank shaft (not shown) by' means of the usual connecting rod 3. The bottom end of this cylinder is closed by a cylinder cover 4 provided with a stufling box 5 through which the piston rod 6- passes. The piston 2 is preferably hollow and the cylinder cover conforms to its internal shape as shown. The combustion chamber of the cylinder is located at the top of the piston and is provided with the usual sparking plug at 7 and inlet and exhaust valves. The part of the cylinder below the piston constitutes a steam expansion chamber, the steam being admitted to this steam. chamber and exhausted therefrom through the piston slide valve 8 operating in the steam chest 9. The wall of the cylinder 1 is comparatively thin and is provided with ribs cast integral with it and these ribs are preferably thickened at the roots 11. A

wrought steel sleeve 12 encircles the ribs 10 the cylinder which carries the necessary valves. These valves are carried preferably in tubular extensions proceeding from the .head to permit of good water circulation.

The ribs 10 do not extend the full length of the cylinder but extend over the high pres sure zone. The sleeve 12 may be lagged in any suitable manner. The cylinder head 13 carrying the sparking plug and valves is provided with water spaces which are in communication with the cylinder acket spaces between the cylinder wall and the sleeve 12 aforesaid.

The numeral 1 1 designates a steam boiler which is arranged with the water level above the crown of the cylinder jacket and a pipe 15 leads from this boiler and is connected by the passage 16 with the cylinder jacket formed as aforesaid by the pressure resisting sleeve 12. A second pipe 17 leads from the cap or cover 13 back to the boiler 14 and thus a complete water circulation is pro vided from the boiler to the cylinder jacket and from the cylinder jacket back to the boiler, the cylinder acket forming a definite part of the boiler system. A pipe 18 conducts the exhaust from the combustion chamber to the steam boilcr which may also be provided with additional firing means for starting and overload purposes as will. be readily understood by those conversant with this type of engine. The eX- haust gascspass along the tire tubes 19 of the boiler into a smoke box 20 in which a. feed water heater 21 is located. A steam pipe 22 leads from'thc boiler 14 to the steam chest 9. The provision of the ribs 10 on the cylinder body not only provides in conjunction with the sleeve 12 an effective means for strengthening the otherwise weakened cylinder walls, but it also provides ample surfaces over which the water can circulate while the removability of the sleeve 12 provides for the ready inspection and cleaning of the outer surfaces of the cylinders and the inner surfaces of the jacket pressure resisting sleeve. Where the sleeve 12 is removable it is preferably turned taper and forced over the ribs 10 so as to produce tension within it on erection so as Lo obviate any tendency upon the part of the cylinder to crack before the strain is transmitted to the sleeve. lit is not however essential for the sleeve to be removable and in Figs. 3, 4: and 5 it have shown an example where the sleeve designated by the numeral 23 is shrunk on to the ribbed cylinder 2% and a flange 25 forming part of the cylinder and the bottom of the water jacket. In this case the cylinder head 26 in the form of a hollow drum is remov able being provided with grooves 27 which fit on to the tops of walls of the cylinder 2 and sleeve 23 and is secured in position by studs 28 which screw into certain of the ribs 29 cast on the cylinder wall. The hollow drum 26 forming the cylinder head carries the usual sparking and valve arrangements,

' the ports 30 of the valves passing through th s drum. The drum has water circulation ports such as 31 for permitting the circnla "tion of water from the jacket to the drum.

The ports 31 are so located that a port occurs over each space between the ribs of the cylinder as shown in Fig. 5. The water from the boiler enters the jacket through the opening 32 and passes into the drum. 28 and back to the boiler through the opening 33 the drum in the manner described in relation to Fig. 1.

In Figs. 6 and 7 I have shown a cy cie engine constructed upon the same liges that described in the specification of prior British Letters Patent l lo. of 1910. In this type of engine owing to necessity for valve chambers 34 surrounding the cylinder wall, the sleeve 35 cannot eonveniently be passed over the pressure Zone. In order to enable the present invention to be applied to this type of engine, 1. construct the cylinder in three portions, a central ribbed portion 36 surrounding the zone and two end portions 3T By means the sleeve 35 is arranged on the per-- pressure 1 .s

tion 36 of the cylinder before the engine is assembled: Rings 39 are used to close the ends of the water jacket which here again forms part of the circulating system of the boiler as before described. The cylinder portion 36 is placed upon and supported by the flange or table 40 cast on the cylinder portion 38 which is shown in this exampl integral with the engine frame. The uppe" portion 37 of the cylinder rests upon and i supported by the top ring 39 aforesaid and the two cylinder ends 87 and 33 are drawn together by long bolts (not shown). These bolts pass close to the sleeve 35 and are embedded in the lagging around the sleeve. The portions 37 and 38 of the cylinder as a whole form the steam expansion chambers of the engine and they are provided with sockets 4-1 and 42 in which steam circulates on its way to the steam chest. During the working 0 than that of the sleeve The cylinder 36 will therefore expand to a greater extent than the sleeve and in so doing probably set up excessive strains Within the structure. I propose to relieve the structure of these strains by constructing the rings 39 as shown in Fig. 7. They are rounded on the surface abutting against the top and bottom castings as shown at 43 and are reduced in thickness by providing in each of them a groove 44. The pressure produced by the expansion of the cylinder will cause sufficient distortion of the rings to relieve these strains and prevent injury to the packing or other jointing material.

What I claim and desire to secure by Letters Patent is:

111 an internal combustion engine, a cylinder oi abnormal thlnness and incapable of withstanding the Working pressures inciden'tal to the operation of the engine, longitudinal ribs cast integral With the cylinder, openings in the ribs to permit of the circulation of the cooling medium, and a pressure resisting jacket shrunk on the cylinder in compressive engagement With the 

